# NTSB GAA19CA216: Bell 47G, N96671, Donna, TX, April 17, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: April 17, 2019, 11:08 local (16:08 UTC) - Place: Donna, TX - Coordinates: 26.204444, -98.051666 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=26.2044&lon=-98.0517&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report November 6, 2019 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 99288 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA19CA216 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99288/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99288 - Page: https://openairdocs.org/ntsb/GAA19CA216 ## Probable cause The pilot's failure to maintain altitude during an agricultural application flight. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: altitude](https://openairdocs.org/ntsb-findings/01062012): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Bell 47G-3B-1, 2 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md?model=1181028), [All aircraft, 1,310 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Bell 47G-3B-1, 6 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=1181028), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Wind: gusts](https://openairdocs.org/ntsb-findings/03034045): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Bell 47G-3B-1, 1 case](https://openairdocs.org/ntsb-findings/03034045/cases.md?model=1181028), [All aircraft, 1,199 cases](https://openairdocs.org/ntsb-findings/03034045/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Other weather encounter](https://openairdocs.org/ntsb-events/400); cases with it: [Bell 47G-3B-1, 1 case](https://openairdocs.org/ntsb-events/400/sequence.md?model=1181028), [All aircraft, 1,127 cases](https://openairdocs.org/ntsb-events/400/sequence.md) - [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Bell 47G-3B-1, 2 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=1181028), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) - [Maneuvering-low-alt flying: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Bell 47G-3B-1, 1 case](https://openairdocs.org/ntsb-events/060/sequence.md?model=1181028), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) ## Analysis The helicopter pilot reported that, during an agricultural application flight and while heading east about 3 ft above ground level, the "wind suddenly shifted, a gust of wind [came] from the west," and the helicopter "settled." The pilot increased power and raised the collective, but the helicopter impacted terrain. The helicopter sustained substantial damage to the fuselage and tailboom. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation. The pilot further reported that the helicopter was equipped with a muffler, which he believed adversely affected the engine's performance. However, correspondence with the helicopter's certificate holder stated that there would "be no reduction of horsepower with the muffler installed if done as per the instructions per the STC [supplemental type certificate]." An automated weather observation station located 5 nautical miles east of the accident site reported that, about 8 minutes before the accident, the wind was from 180° at 16 knots, gusting to 25 knots and that, about 32 minutes after the accident, the wind was from 180° at 16 knots, gusting to 26 knots. ## Factual narrative The helicopter pilot reported that, during an aerial application flight with an easterly heading, about 3 feet above ground level, the "wind suddenly shifted, a gust of wind [came] from the west" and the helicopter "settled." The pilot increased power and raised the collective but the helicopter impacted the terrain. The helicopter sustained substantial damage to the fuselage and tail boom. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation. The pilot further reported that the helicopter was equipped with a muffler, which he believed adversely affected engine's performance. Correspondence with the certificate holder of the helicopter, "determined to be no reduction of horsepower with the muffler installed if done as per the instructions per the STC." The automated weather observation station located 5 NM east of the accident, reported that, about 8 minutes before the accident, the wind was from 180° at 16 knots, gusting to 25 knots. The same automated station reported that, about 32 minutes after the accident, the wind was from 180° at 16 knots, gusting to 26 knots. ## Aircraft - Registration: [N96671](https://openairdocs.org/deregistered/N96671-2022-07-02), registration cancelled 2022-07-02, S/N 3539, built 1967 (OpenAirDocs) - Reported make and model: Bell 47G (3B1) - Registry model: [Bell 47G-3B-1](https://openairdocs.org/model/bell-47g-3b-1) (registry code 1181028) (OpenAirDocs) - Registry engine: [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series) (registry code 41525, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 3539 - Year built: 1967 - Engines: Lycoming VO-435-A1F 265 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Hendrickson Flying Service - Registered owner: Turnquist Lee W - Airworthiness certificate: Standard, Normal; Special, Restricted (Special) - Departed: TXW, Weslaco, TX - Destination: TXW, Weslaco, TX - Equipment: ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; injuries: none; commercial; medical: class 2, with waivers/limitations; last flight review June 14, 2017; seat: left; flight hours: 12,500 total, 6,000 in this make and model, 12,100 as pilot in command, 5 in the last 90 days, 5 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 16 knots, gusting 25 - Visibility: 7 statute miles - Lowest ceiling: 1,900 ft broken - Temperature: 82 °F, dew point 72 °F - Altimeter: 29.80 inHg - Observed at: KTXW, 5 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20190417010829A](https://openairdocs.org/incident/20190417010829A), Apr 17, 2019: Bell 47G-3B-1, Donna, TX, Substantial damage. A Bell 47 aircraft bearing registration Number N96671, registered to hendrickson flying service inc, impacted terrain during an aerial spraying operation north… ## Other investigations on N96671 (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB CHI81FER60](https://openairdocs.org/ntsb/CHI81FER60), Aug 12, 1981: Bell 47G3B1 (N96671), Stewart, MN, substantial damage ## Docket (3 files) The files NTSB released with the investigation on May 15, 2019, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99288. 953 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 530 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472927&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Weight and Balance Email (item 2, .PDF, 78 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472928&FileExtension=.PDF&FileName=Weight%20and%20Balance%20Email-Master.PDF - Accident Photos (item 3, .PDF, 2 photos, 345 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472929&FileExtension=.PDF&FileName=Accident%20Photos-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.